Relay catalysis of Pt single atoms and nanoclusters enables alkyl/aryl C-O bond scission for oriented lignin upgrading and N-functionalization

The controllable scission of the alkyl/aryl C-O bond is of great consequence for the selective valorization of lignin-containing biomass feedstocks. Herein, a renewed heterogeneous catalyst (PtSA/NC-AMP) comprising both Pt single atoms and nanoclusters supported by Al(PO3)3 was developed to be highly effective for hydrogenative scission of alkyl/aryl C-O bonds in lignin derivatives and various oxygenated aryl/alkyl compounds to arenes and alkanes, respectively. The relay catalytic process enabled by the finite size effect was considered to be accountable for the excellent reactivity, where Pt single-atom sites predominantly contribute to H2 dissociation into active H atoms, while Pt nanocluster sites significantly expedite C-O bond scission via hydrodeoxygenation. Moreover, the size-dependent strong metal-support interaction of Pt-Al(PO3)3 performed a crucial role in strengthening the reactivity and stability of PtSA/NC-AMP. The relay catalytic strategy based on the finite size effect provides a reference for multi-step upgrading of biomass involving oriented alkyl/aryl C-O bond rupture.